POS1141 FACTOR ANALYSIS OF FRAGILITY FRACTURES BY SITE IN PATIENTS REFERRED FOR DUAL-ENERGY X-RAY ABSORPTIOMETRY SCAN
Authors: Z. Sultan, M. Bukhari
Journal: Annals of the Rheumatic Diseases (2022)

Background Fragility fractures are defined as fractures which occur secondary to low energy trauma (1). Fractures lead to substantial pain, reduced quality of life and significant burden to society, with 3.5 million fragility fractures occurring in the EU in 2010 costing €37 billion (2). It is predicted that by 2025 this cost will have increased by 25% (2). Studying fractures is in the interest of our ageing society in order to aid management of patients at risk. To our knowledge, no other studies have grouped fractures based on site by factor analysis. Objectives 1.Determine which fractures are most common in patients who present for dual-energy X-ray absorptiometry (DEXA) scan 2.Apply a factor analysis to establish any patterns in the incidence of fractures based on site Methods Between 1996 and 2017, 31546 patients presented to a district general hospital in the North West of England for bone mineral density estimation by DEXA scan. Demographic details, risk factors, incidence of fractures and site of fractures were recorded at time of scan. These data were retrospectively studied to identify patients who had sustained at least one fracture. STATA was used to conduct a factor analysis using the principal component factors (PCF) method. Ethical approval was granted by the Northwest Regional Ethics Committee. Results 11839 patients were identified to have had at least one fracture (14756 total fractures). Mean age was 67.96, with 9993 females and 1846 males. Mean height was 161.21 cm, mean weight was 70.41 kg and mean BMI was 27.04 kg/m2. Mean T-scores at femoral neck, total femur and lumbar spine were -1.55, -1.38 and -1.30 respectively. The most common fracture site was at the wrist/forearm with 5421 (36.74%) cases. Further, there were 2795 tibia/fibula (18.94%), 2530 spine (17.15%), 1363 femur (9.24%), 1224 humerus (8.29%), 1063 rib (7.20%), 315 pelvis (2.13%), 43 elbow (0.29%) and 2 ankle (0.01%) fractures. 9390 patients had 1 fracture and 2449 patients had more than 1, with 9 patients sustaining 5 fractures. Factor analysis on fracture sites revealed 6 factors with an eigenvalue &gt; 1. Fracture sites were grouped together based on those fractures which loaded most heavily on each factor. Loading was as follows: spine and ribs on Factor 1; spine, pelvis and wrist/forearm on Factor 2; humerus and femur on Factor 3; elbow and ankle on Factor 4; ribs and humerus on Factor 5; ribs and femur on Factor 6 (Table 1). Table 1. Factor analysis on sites of fractures using the PCF method. Variable Factor 1 Factor 2 Factor 3 Factor 4 Factor 5 Factor 6 Uniqueness Tibia/fibula 0.0862 -0.9485 -0.0530 0.1182 0.0325 -0.0896 0.0671 Spine 0.6906 0.3263 -0.4535 -0.1501 -0.2681 -0.1837 0.0829 Ribs 0.2128 0.1089 -0.0689 -0.0957 0.7535 0.6074 0.0193 Pelvis 0.0810 0.2050 0.1185 -0.0158 0.2113 -0.3663 0.7368 Humerus 0.0386 0.1433 0.5578 0.0892 0.3832 -0.5101 0.2518 Femur 0.1227 0.0946 0.7052 0.0071 -0.4814 0.4532 0.0416 Elbow 0.0397 0.1300 -0.0740 0.7306 0.0305 0.0363 0.4401 Ankle 0.0547 0.1082 -0.1084 0.7189 -0.0365 0.0716 0.4503 Wrist/forearm -0.8856 0.2389 -0.2461 -0.0479 -0.0608 0.0071 0.0920 Conclusion In-keeping with published data, the most common site for fracture was forearm (3). Factor analysis grouped together sites of fractures into 6 factors, suggesting that these fractures are more likely to co-exist. Moving forward it would be beneficial to ascertain differences between the groups in terms of demographics, risk factors and any bone protection measures taken. This may highlight clinically relevant data in order to make evidence based decisions in the identification and management of patients at risk of fragility fractures. References [1]National Institute for Health and Care Excellence (NICE). Osteoporosis: assessing the risk of fragility fracture - Clinical Guideline (CG146). 2012;(August) [2]Svedbom A. et al. Osteoporosis in the European Union: a compendium of country-specific reports. Arch Osteoporos (2013) 8:137 [3]Johnell, O., Kanis, J.A. An estimate of the worldwide prevalence and disability associated with osteoporotic fractures. Osteoporos Int 17, 1726–1733 (2006) Disclosure of Interests None declared